The invention relates to a clamping device for saw blades, in particular in motor-driven straight-back and saber saws.
In the known motor driven straight-back and saber saws, the saw blades are secured to clamping devices of a lifting rod. This requires using additional tools to fasten the saw blade securely and in form-locking fashion to the clamping device. Changing the saw blade can generally be done only whenever the lifting rod is in a certain position.
The conventional clamping devices also have the disadvantage that the screws that have to be tightened to fix the saw blade can loosen during operation, since considerable forces are exerted precisely in straight-back and saber saws.
The object of the present invention is therefore to create a clamping device which overcomes the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in a clamping device for saw blades, which is formed so that a saw blade rests between a clamp holder and a movable clamping piece, the clamping piece is formed as a wedge on a side remote from the saw blade, a wedge piece is formed as a wedge on a side which rests on the side of the clamping piece, and the wedge piece is movable by a spring so that the clamping piece presses against the saw blade.
The clamping device for saw blades according to the invention has the advantage over the prior art that without an auxiliary tool and using only a single handle piece, the saw blade can be mounted and unmounted conveniently and quickly and without the risk of injury. According to the invention, the saw blade is fixed in a clamp holder by means of two wedges acting counter to one another. The forces required for the contrary motion of the wedges are brought to bear by springs.
Changing the saw blade can also be done in any lifting position, so that to change the saw blade it need not be moved to a particular position.
The wedgelike design of the clamping pieces also creates self-locking, because of the steeply sloped planes formed between the clamping pieces and the wedge piece. This leads to a secure hold of the saw blade and to form-locking guidance of it.
It is advantageous to embody the wedge-like sides of the clamping piece or of the wedge piece as either convex or concave, with the opposed wedgelike piece being shaped in the respectively other way. This brings about easier friction of the faces against one another.
By actuating a handle piece that is secured to the housing, the saw blade can also be released with one hand, so that the saw blade can then be removed from the clamping device.